[FFmpeg-user] Zeranoe Windows builds spiking CPU to 100% randomly

Jan Ehrhardt phpdev at ehrhardt.nl
Wed Jul 11 23:33:13 CEST 2012

Roger Pack in gmane.comp.video.ffmpeg.user (Wed, 11 Jul 2012 15:13:26
>> What still strikes me: on my most troublesome file (50i PAFF interlaced
>> Canon HF M306 recording) the ancient Mencoder-33883 is as quick as or
>> even faster than the fastest FFmpeg. See output below.
>That seems odd since I'd guess that mencoder just "calls out" to
>ffmpeg underneath, anyway (or libavcodec or what not).  You could
>compare it to some "ancient" versions of ffmpeg I suppose :)

Odd, but true. Underneath is a FFmpeg 0.8.1 which on its own is sloooow.
But when called from within Mencoder it is really quick. Somehow
Mencoder grabs more of the available CPU power:

>> BTW. Both FFmpeg and Mencoder are incorrect about the input framerate.
>> They think it is 25, but for a correct transcode it should be 50.
>I'd submit it with a small reproducible test sample to the ffmpeg trac.

The command lines were wrong. FFmpeg only needs a -r 25 for the output

-i %input% -r 25 -vf scale=384:288 -aspect 4:3 -sws_flags bicubic
-threads %NUMBER_OF_PROCESSORS% -vcodec wmv2 -b:v 320k -acodec wmav2 -ab
64k -ar 44100

Source: http://x32.elijst.nl/00005.MTS

I will dd the file later and file something at the trac.


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